Revert "Remove ancient support for kUnknown_SkColorType in SkBitmapDevice"

This reverts commit e3a5b1960dfb7380b116ed3e93d3a1c930139a09.

Reason for revert: possibly breaking chrome roll

Original change's description:
> Remove ancient support for kUnknown_SkColorType in SkBitmapDevice
> 
> Bug: skia:
> Change-Id: I7559544f46b49be5ac6b38add8d1b61c010d3d6f
> Reviewed-on: https://skia-review.googlesource.com/c/162284
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>

TBR=mtklein@google.com,brianosman@google.com,reed@google.com

Change-Id: I95d502f80fc3c336484b306b50c9b5fe16f26a82
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/c/163040
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
1 file changed